Various methods of power control for wireless communication systems are well known in the art. An example of an open loop power control transmitter system for a single rate data system is illustrated in FIG. 1. An example of a closed loop power control transmitter system for a single rate data transmission is illustrated in FIG. 2.
The purpose of both systems is to rapidly vary transmitter power in the presence of a fading propagation channel and time-varying interference to minimize transmitter power while insuring that data is received at the remote end with acceptable quality. Typically, in a digital implementation, transmitter power is varied by applying a varying scale factor to the digital data, as opposed, for example, to varying the gain of an RF amplifier.
In state-of-the-art communication systems such as Third Generation Partnership Project (3GPP) Time Division Duplex (TDD) and Frequency Division Duplex (FDD) systems, multiple channels of variable rate data are combined for transmission. FIGS. 3 and 4 represent prior art open and closed power control transmission systems, respectively. Background specification data for such systems are found at 3GPP TS 25.223 v3.3.0, 3GPP TS 25.222 v3.2.0, 3GPP TS 25.224 v3.6 and Volume 3 specifications of Air-Interface for 3G Multiple System Version 1.0, Revision 1.0 by the Association of Radio Industries Businesses (ARIB).
Such open and closed loop power control systems for variable multirate wireless communications systems respond relatively slowly to data rate changes, resulting in sub-optimal performance such as relating to excessive transmitter power and below-quality received signals. It would be desirable to provide a fast method and system of power control adaptation for data rate changes resulting in more optimal performance.